Abstract
Purpose:
Amblyopia is one of the most common causes of uncorrectable visual impairment in children. The objective of this analysis is to estimate the age-, gender-, and ethnicity-specific prevalence of amblyopia using data from eight sites in the multi-country Refractive Error Study in Children (RESC)
Methods:
Population-based, cross-sectional samples of children aged 5 to 15 years were selected through random cluster sampling. The examination included visual acuity measurements, evaluation of ocular alignment and refractive error under cycloplegia, as well as examination of the external eye, anterior segment, media, and fundus. Amblyopia was defined as best-corrected visual acuity of 20/40 or less in either eye, with tropia, anisometropia (2 spherical equivalent diopters or more) or hyperopia (+6 spherical equivalent diopters or more), after excluding children with fundus or anterior segment abnormalities
Results:
Among 46,260 children who were enumerated, 39,551 had a detailed ocular examination and a reliable visual acuity measurement in one or both eyes. Information on ethnicity was available for 39,321 of these participants.The overall prevalence of amblyopia was 0.74% (95% confidence interval: 0.64%-0.83%) with significant (p<0.001) variation across ethnic groups: 1.43% in Hispanic, 0.93% in Chinese, 0.62% in Indian, 0.52% in Malay, 0.35% in Nepali and 0.28% in African children. Amblyopia was not associated with age or gender. The most common cause of amblyopia was anisometropia.
Conclusions:
On average, amblyopia affected approximately 7 per thousand school-aged children in this study. Amblyopia was more prevalent in people of Hispanic and Chinese ethnicity. Most cases are unilateral and appear to develop before the age of 5 years.